Safari rear differential noise

[Crisyrn63]

1999 Safari Serengetti. Experiencing loud noise on deceleration. Had rear end differential taken apart - OK. Still having this loud noise. anyone else have this and how do you fix it?

[jplante4]

A '99 Serengetti is probably a Magnum chassis with a CAT 3126B 300 horse. I'd guess U-joint (there's a fairly short drive shaft that is usually ignored at lube time) or the PAC brake is acting up. Make sure the PAC brake is off and see if that fixes the issue. Crawl under and try to move the driveshaft and see if the U-joint has any slop.

[Dave_H_M]

I had that in my chev suburban and in my 8N ford tractor. Both time - bearings. :h

[j-d]

This post is a first post by a new member, so first: Welcome, Glad you found us, You can Learn, and before long You will be Helping!

More Details please: Engine, Transmission, Chassis! This is an elite Diesel Pusher, more in common with a Greyhound Bus than the Box Trucks most of our RV's are based on. How'd you get it? Miles? Condition? Previous Work on it?

My experience with DP's rounds off to None, but I'll pray it's what I'll call Deceleration Noise. One way or another, your powertrain (Engine, Transmission) rest on flexible Engine Mounts. When you accelerate, those mounts allow the powertrain to transfer torque to the wheels, without the engine flopping over on its side back there. When you slow down, your powertrain tries to twist the OTHER WAY as your gearing, probably Engine Brake too, uses engine compression to hold you back.

If an Engine Mount has gone soft or literally broken, it could be OK in Accel and yet cause trouble in Decel. How? By allowing a driveline or exhaust component to rub on a chassis or body component that serves as a sounding board.

It may well take a skilled, experienced, patient tech to find this. The kind of person you might find at a quality OTR (Over The Road) shop. The big Cummins/CAT/Allison operations.

Or, next camper you meet might've heard it, found it, fixed it and done...

Keep us up to date.

[sgip2000]

U-joint.

[time2roll]

They found nothing? Need a better shop.

[MySuncoastRV]

If you have a split drive shaft, climb underneath and attempt to lift the drive shaft up and down. If there is movement, the carrier bearing is bad. You may even have to drop the smaller shaft and recheck for movement .

[ggardne2]

Can you describe the noise? Is it a whining noise or is it a clunk? If this is a deceleration whine it could be a driveline issue related to universal joints, an outboard wheel bearing on the axle, or potentially a transmission issue. If the differential hypoid pattern was OK I would tend to suspect a driveline angle/universal joint problem but would have expected the shop who worked on the differential to inspect the driveline as well.

Was the shop that worked on the differential an experienced driveline shop?